Optical system



Aug. 12 1924. 1,504,970

E. PASCUCCI OPTICAL SYSTEM 1921 3 Sheets-Sheet Filed Julv 19 Emilio Pascum:

INVENTOR ATTORNEY OPTICAL SYSTEM Filed July 19 1921 3 Sheets-Sheet 2 E mfliu Pa 5 E u c [:1

INVENTOR BY k Aug. 12, 1924. 1,504,970

CCCCCCCC Cl SYSTEM Flled July 19 v 1921 BY W m; M ATTORNEY Patented Aug. 12, 1924.

UNITED STATES PATENT OFFICE.

EIILIO PASCUCCI, OI' CORNING, NEW YORK, ASSIGNOR TO CORNING GLASS WORKS, OF

CORNING, NEW YORK, A CORPORATION OF NEW YORK.

OPTICAL SYSTEM.

Application filed July 19, 1921. Serial No. 486,841.

To all whom it may concern:

Be it known that I, Emmo PASCUCCI, a citizen of the United States of America, and a resident of Coming, New York, have invented certain new and useful Improvements in Optical Systems, of which the following is a specification.

Certain disadvantages are present in the lenses now in common use with a smooth to outer convex face and a corrugated or stepped inner face; Among these disadvantages are the loss of light falling on the -m1ters and projected thereb out of the edges thereof as to render t em ineliicient 16 in She purpose for which such lenses are use My invention has for its object to avoid these and other defects of the previous construction and for this purpose I em loy a 20 corrugated lens formed from presse glass and having its corrugated inner face provided with miters or steps whose lower faces are on the same angle as the path of the internal rays, i. e., a corrugated lens having miters that are undercut.

It is obvious that it would be exceedingly difficult to produce a lens having undercut miters in the usual manner, as by pressin the entire lens in one piece. Therefore,

have, as an embodiment of this invention,

shown means whereby such lens can be produced by pressing segments specifically, in the form of quadrants, but the lens can be made of sectors of an are equally as well.

The invention will claimed at the end hereof, but will be first described in connection with the accompanying drawings, in which Figure 1, is a vertical section through a 0 corrugated lens having undercut miters, il-

lustrating diagrammatically the path of light rays passing therethrough from a light source;

Fig. 2, is a view of the inner face of the lens shown by Fig. 1;

Fig. 3, is a plan of a mold used in pressing a quadrant of the lens the parts of the 'mold being shown assembled by 1111 lines, and the mold ring being shown separated by dotted lines, to ermit the sector of the lens to be removed f' fom the mold; and

Fig. 4, is a vertical longitudinal section through the mold, all of theedparts being shown in the position assum when the mold-plunger has completed its downward stroke.

Referring to the drawings, the lens 10 (Figs. 1 and 2) has a convexed front face 11, and a rear face composed of a series of zones 12-13, 14-15, 16-17, 18-19, 20-21 which are united by miters or steps 13-14, 15 1e, 17-18, 19-20, 21-22, and is 8111 rounded by a flange 23 by means of which the lens can be secured in a lamp frame (not shown).

The miters 13-14, 15-16, etc., of the lens are formed, as shown, each of the miters being inclined at an angle with res ect to the axis of the lens whereby they Wlll each be undercut, and their diameters at the points 14, 16, 18, and 20, will be greater than their diameters at the points 13, 15, 17 and 19 respectively.

With such lens when properly placed in front of a source of illumination 24 no dark bands coinciding with the positions 2f located substantially in the path in which the rays from the source pass through the lens at the several miters and hence practically none of the rays falling thereon are lost. This is illustrated by ollowing the course of any ray. For instance, the ray 24-25 falls upon the rear face of the lens at a proper point to be refracted theretlrough on a line parallel to the miter 1 -18.

It is obvious that a lens constructed as above described can not be made in the usual manner, and, therefore, I have shown the lens 10 com osed of similarly formed segments A, B and D (see Fig. 2). The segments can be in the form of the quadrants illustrated, or they can be of an other size. These segments can be ma e with the use of a glass press mold, such as that shown by Figs. 3 and 4 of the drawings.

The mold comprises a base 30 having a raised rtion 31 whose up r surface corresponds to the inner face 0 one segment of the lens. Adapted to surround the raised portion 31 of the base 30 and enga there- 106 with, is a mold-rin 32 composed 0 similarly formed halves Slat are hin ed together preferably at the apex of t e segment.

an el iugs sl i- This is due to the act'tliat' the miters are b The mold ring is provided with an angular flange 33 along its base that is designed to engage with a similarly formed groove 34 in the base 30. The mold-ring 32 is providcd with a groove 35 in which the flange 23 of the lens 10 is formed as shown by Fi 4 of the drawings.

The mold-ring 32 is of suflicient he1ght to form a guide way for a plunger 36 which is adapted to be operated in any ap roved manner. The contour of the lower of the plunger 36 is such that the convexed front face of the segment of the lens will be formed.

In the operation of forming the segmcnts of the lens, the mold is first assembled with the mold-ring 32 engaging with the raised portion 31 of the base 30, the ring being retained in closed position by means of a locking pin 37. A suitable quantity of molten glass is then deposited in the mold, and the plunger caused to descend and distribute the lass throughout the mold cavity. When the glass has set, the plunger is withdrawn from the mold and the halves of the mold-rin separated as shown by the dotted lines 1g. 3. The segment is then removed from the mold by means of tongs, or any other suitable implements, which are used to grasp the flange 23 of the segment. Due to the construction of the miters it is desirable that the segment be withdrawn from raised portion of the mold base in a substantia 1y horizontal plane. It is only necessar to open the halves of the mold-rin su ciently to permit the withdrawal of the segment, after which the mold-ring can be closed and the operation repeated.

It is to be understood that while I have in the resent instance shown a type of lens similar to those used in semaphores in connection with railway signalling, m invention can be used in connection wit all other types of corrugated lenses, such for instance as the corrugated lenses havin negative spherical aberration that are use for condensers in optical projection apparatus.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. A Fresnel lens having on one face concentric zones united by miters, the miters being undercut, whereby they will be parallel to the path of the rays passing through the lens.

2. A Fresnel lens having a stepped face consisting of concentric zones united by miters the miters being undercut wherdiy they will be parallel to the paths of the rays assing through the lens, said lens being ormed from segments.

3. A corrugated lens having concentric miters undercut whereby such miters will be substantially parallel to the rays passing through the lens, said lens being composed of pressed segments.

4. The combination with a light source, of a Fresnel lens receiving divergent rays from the source, having on the face receiving such rays concentric zones united by miters, the miters being undercut, whereby they will be parallel to the path of the rays passing through the lens.

11 testimony whereof, I hereunto sign mv name at Corning, New York, U. S. A., this 9th day of July, 1921.

EMILIO PASCUCCI. 

